Archive for the ‘Temperature projections’ Category

“Climate change may be far worse than scientists thought, causing global temperatures to rise by at least 4 degrees Celsius by 2100, or about 7.2 degrees Fahrenheit, according to a new study.

The study, published in the journal Nature, takes a fresh look at clouds’ effect on the planet, according to a report by The Guardian. The research found that as the planet heats, fewer sunlight-reflecting clouds form, causing temperatures to rise further in an upward spiral.

“4C would likely be catastrophic rather than simply dangerous,” lead researcher Steven Sherwood told the Guardian. “For example, it would make life difficult, if not impossible, in much of the tropics, and would guarantee the eventual melting of the Greenland ice sheet and some of the Antarctic ice sheet.”

Another report released earlier this month said the abrupt changes caused by rapid warming should be cause for concern, as many of climate change’s biggest threats are those we aren’t ready for.”

“The debate around the accuracy of climate modelling and forecasting has been especially intense recently, due to suggestions that forecasts have exaggerated the warming observed so far – and therefore also the level warming that can be expected in the future. But the new research casts serious doubts on these claims, and should give a boost to confidence in scientific predictions of climate change.

The paper, published on Wednesday in the journal Nature Geoscience, explores the performance of a climate forecast based on data up to 1996 by comparing it with the actual temperatures observed since. The results show that scientists accurately predicted the warming experienced in the past decade, relative to the decade to 1996, to within a few hundredths of a degree.

The forecast, published in 1999 by Myles Allen and colleagues at Oxford University, was one of the first to combine complex computer simulations of the climate system with adjustments based on historical observations to produce both a most likely global mean warming and a range of uncertainty. It predicted that the decade ending in December 2012 would be a quarter of degree warmer than the decade ending in August 1996 – and this proved almost precisely correct.”

Like this:

“In a report issued on the penultimate day of new UN talks in Bonn, scientists said Earth’s average global temperature rise could exceed the dangerous 3.5 C (6.3 F) warming they had flagged only six months ago. Marion Vieweg, a policy researcher with German firm Climate Analytics, told AFP the 3.5 C (6.3 F) estimate had been based on the assumption that all countries will meet their pledges, in themselves inadequate, to reduce greenhouse-gas emissions. New research has found this is not “a realistic assumption,” she said, adding that right now “we can’t quantify yet how much above” 3.5 C (6.3 F) Earth will warm.”

Ongoing climate change means that summer Arctic sea ice could be halved, runoff in the South Saskatchewan River basin reduced and the cost of shipping through the Great Lakes and St. Lawrence Seaway could rise due to lower water levels, according to a compilation of research published Tuesday.

Billed as the first comprehensive illustration of expected climate impacts in Canada, the report is a joint project of the National Round Table on the Environment and the Economy (NRTEE) and the Royal Canadian Geographical Society (RCGS), which publishes Canadian Geographic and Géographica magazines.

The October issue of the magazines feature the compiled research, including a diagram outlining 60 effects of climate change at increasing levels of warming.

“I think it’s important to get the correct science information in Canadian hands,” NRTEE chair Robert Page said Tuesday at an Ottawa news conference called to release the data. “What I like about this (report) is it’s an attempt to bring it back to an accepted factual base.”

The scenarios about Arctic sea ice, the South Saskatchewan River and the Great Lakes are premised on a temperature increase of 2 C over pre-industrial levels.

That temperature rise is significant because the United Nations climate change summit in Copenhagen last December ended with a non-binding document aiming to limit world temperature increases to no more than 2 C. Globally, temperatures have already risen by 0.8 C over the past century.

But as Page pointed out, the increase in temperature in Canada is expected to be twice the world average, and parts of the Canadian North are expected to experience a rise in temperature that is twice the Canadian average.

Yet as the compiled research shows, not all impacts in Canada are negative. For example, a 2 C increase could bring increased timber yields from faster-growing trees in the North and more Atlantic cod north of the 60th parallel. The ski industry might struggle, but golfers could benefit from warmer temperatures.

The society and roundtable have also produced an education package based on the compiled research, which will be distributed to 12,000 schools across Canada.

On Tuesday evening, the two groups hosted a reception at the Canadian Museum of Nature where Canada’s new Gov. Gen. David Johnston spoke.

Canada’s Arctic sea ice might be halved, runoff in the Saskatchewan River basin would be reduced, and shipping through the Great Lakes and the St. Lawrence Seaway could cost more, according to a report on climate change released in Ottawa.

The research is covered in depth on the website of the roundtable, as well as in the October issue of Canadian Geographic, which features a wide range of articles on climate change’s effect on Canadian resources, Halifax’s rising harbour, and the impact on global warming on health care.

Also available is a detailed poster/map that looks at what would happen to Canada if the temperature increases between 1 and 5 degrees Celsius.

Other changes facing Canada if temperature increase could include: Western mountain glaciers losing 50 per cent of their volume; exposure to vector borne diseases, more deaths from heat waves; loss of boreal forest and tundra; compromised water quality; more deaths from poor air quality; polar bear subpopulations at risk of extinction; and more water-borne disease outbreaks.

Average world temperatures are now up 0.78 degrees C compared to before the industrial revolution over a century ago.

The United Nations climate-change summit in Copenhagen last December ended with a non-binding document that limited world temperature increases to no more than 2 degrees C.

If national targets are not revised in the Copenhagen Accord, the international pledge which was agreed at last year’s Copenhagen’s COP15 climate change conference, a global temperature increase of up to 4.2º C and the end of coral reefs could become reality by 2100.

Just ahead of the next United Nations Climate Change Conference, which starts on 4 October in Tianjin, China, a new report published yesterday (September 29), in Environmental Research Letters describes how, due to lack of global action to date, only a small chance remains for keeping the global temperature increase down to 2º C, the Accord’s target.

Looking at individual countries’ agreed targets for emission levels, the report shows that many developed countries such as the USA and the European Union have set their aims very low, aiming at reaching emission levels just a few percent lower than 1990 levels by 2020.

Japan and Norway are aiming to drastically reduce their emission to 25 per cent and 30 to 40 per cent below 1990 levels respectively.

Presenting their results in Environmental Research Letters, the researchers have found that even if nations would agree to a 50 per cent reduction of emission levels by 2050 there would still only be a less than 50 per cent chance to keep global warming below 2º C.

Rising global temperature levels would not be the only consequence of failing to raise the ambition level of future global emission reductions. Increasing ocean acidification could lead to a rapid decline of coral reefs and the marine ecosystem in the 21st century.

Urgent action is necessary, the authors write. “It is clear from this analysis that higher ambitions for 2020 are necessary to keep the options for 2º C and 1.5º C open without relying on potentially infeasible reduction rates after 2020.

“In addition, the absence of a mid-century emission goal — towards which Parties as a whole can work and which serve as a yardstick of whether interim reductions by 2020 and 2030 are on the right track — is a critical deficit in the Copenhagen Accord.”